Packing element and method

ABSTRACT

A packing element includes a mandrel, at least one seal member having a Chevron shape and composed of a metal material, and an energizer in operable communication with the at least one seal member and a method for packing a tubular.

BACKGROUND OF THE INVENTION

Packing elements are well known and often used components of downholeoperations. Packing elements are used for a number of different reasonsin a number of different systems but generally all operate similarly.Packing elements are annular structures used to press against an insideor outside diameter of a target tubular, sometimes sealing thereagainst,to prevent all fluid communication past the packing element/tubularinterface.

While the ubiquity of packing elements clearly evidences theireffectiveness, it will be recognized by those of ordinary skill in theart that because of the elastomeric material utilized in most packingelements, degradation remains a problem for the art. The art istherefore always receptive to alternatives and especially those withgreater robustness.

SUMMARY

A packing element includes a mandrel, at least one seal member having aChevron shape and composed of a metal material, and an energizer inoperable communication with the at least one seal member.

Further disclosed herein is a method of packing a tubular. The methodincludes compressing a packing element, splaying open at least one sealmember to enlarge a radial dimension of the member, and maintainingenergy in the at least one seal member.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings wherein like elements are numbered alikein the several Figures:

FIG. 1 is a quarter section view of a packing element in accordance withthis disclosure in the run in position;

FIG. 2 is a quarter section view of the element of FIG. 1 in the setposition;

FIG. 3 is a quarter section view of an alternative arrangement of apacking element.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, one embodiment of a packing element 10 that is inone iteration free of elastomeric members is illustrated in the run-inposition. The element 10 includes a mandrel 12 upon which is disposed aseries of components. The components include (arbitrarily starting froman uphole end of the packing element 10) a slip 14 in operablecommunication with a moveable ramp 16 disposed upon the mandrel; arelease member 18 (such as a sheer screw) releasably attaching themoveable ramp 16 to the mandrel 12; a series (one or more sealingelements 20) of Chevron shaped seal members 22 disposed between the ramp16 and an energizer 24; another series (one or more sealing elements) ofChevron shaped seal member 26 disposed between the energizer 24 andanother moveable ramp 28; a release member 30 releasably attaching theramp 28 to the mandrel 12; a slip 32 in operable communication with theramp 28, and a ratchet assembly 34.

The packing element 10 is set to create a seal, by being axiallycompressed which causes a compression of each of the componentsnumerically identified above to an axially smaller area. That is, inorder to set the element 10, slip 14 is caused to reside more axiallyproximate to ratchet 34. This can be effected by preventing movement ofratchet 34 while moving mandrel 12 in a direction that brings a mandrelshoulder 36 closer to ratchet 34, thereby forcing all other componentsto also become closer to ratchet 34; by moving mandrel 12 in the samedirection while moving ratchet 34 in an opposing direction; and byfixing the mandrel in place and moving the ratchet 34 toward mandrelshoulder 36. In each case, the axial distance between mandrel shoulder36 and ratchet 34 is reduced thereby compressing all intermediarycomponents into a smaller axial space. During such movement of thecomponents hereof, the slips 14 and 32 are caused to move up rampsurfaces 38 and 40, respectively, thereby moving slips 14 and 32radially outwardly of mandrel 12 into interfacing contact with an insidesurface 42 of a tubular (not otherwise shown). Slips 14 and 32 thusprovide anchoring of the packing element 10. The slips 14 and 32 aremaintained in this position by ratchet assembly 34, which ratchets inthe direction of compression of the packing element 10 and preventsmovement in an opposite direction. Contemporaneously with the movementof slips 14 and 32, and as noted above, movable ramps 16 and 28 are alsourged to move toward one another. In the illustrated embodiment,movement is unidirectional, though collectively converging. This can benoted from a review of FIG. 2 with specific attention focused uponrelease members 18 and 30, which are illustrated as shear members, inthe sheared position. The converging relative movement of movable ramps16 and 28 causes an axial load to be applied to seal members 22 and 26as well as to energizer 24, positioned therebetween. In the compressedcondition, the seal members 22 and 26 tend to yield to a configurationthat is flatter, or alternatively stated, more radially directed thanthe condition in which they exist when at rest, (see FIGS. 1 and 2 incomparison). Due to the Chevron shape of each sealing element 20 of sealmembers 22 and 26, a flattening, i.e. a growth, or splaying open of aninside angle alpha, necessarily translates to an increasing radialdistance between an inside edge 44 and an outside edge 46 of eachsealing element 20 of each seal member 22 and 26. Radial growth isprecisely what is needed to seal the annulus between mandrel 12 andinside diameter 42. In addition, because of the directional nature ofthe seal members 22 and 26, utilizing both directions in a singlepacking element 10 ensures that pressure is held from both directions.

Energizer 24, which is a resilient member such as a spring, ensures thatsealing energy stays in the seal members even after multiple pressurereversals in the downhole environment. Such pressure reversals have beena cause of seal leakage and such is avoided in the context of theinvention by employing the energizer 24.

In an alternate embodiment, referring to FIG. 3, the direction of theseal members 22 and 26 is reversed. Sealing is, however, effected insubstantially the same way as the forgoing embodiment since the sameforces are not at work to cause an enlargement of the angle alpha in theChevron shaped members thereby increasing their radial dimensions.

In the foregoing embodiments, the seal members comprise non-elastomericmaterials to enhance resistance of the packing element to downholeenvironmental conditions thereby ensuring a long, useful life of theelement.

Because of the particular configuration of the sealing elements 20 ofeach seal member 22 and 26, a series of relatively narrow annular sealareas are created against both the inside surface 42 of a target tubularand the mandrel 12. This means that ridges and other surfaceirregularities of the target tubular are much more easily accommodatedthan with prior art packing elements having a broader contact surface inone element, where bridging might occur. For example, if a targettubular presents a series of annular irregularities, each of theindividual sealing elements 20 of the seal members 22 and 26 willautomatically adjust to the surface by extending more radially outwardly(limited of course to a maximum radial expansion related to total axialcompression and the ability of the seals to flatten) or by being morehighly loaded against a “high spot” on the casing so that the individualsealing element member does not expand radially to its otherwise fullestpotential. Due to this property, the individual sealing element willcreate individual annular seals that together combine to create a morecompetent packing element while being exceptionally robust.

It is to be appreciated that while a pair of slips is shown and a pairof sealing members is shown, singles of each is also workable whilestill maintaining good sealing properties of the packing element. Insuch a configuration, the seal members 20 or even the energizer 24 couldbe arranged to abut the mandrel shoulder 36, for example, so that energyis storable in the packing element through axial compression thereofagainst the shoulder 36 or similar.

In yet another embodiment, where anchoring is not needed or desired, theseal members 22 (or 22 and 26) may be employed alone with such asratchet assembly 34 to hold energy in the seals.

While preferred embodiments have been shown and described, modificationsand substitutions may be made thereto without departing from the spiritand scope of the invention. Accordingly, it is to be understood that thepresent invention has been described by way of illustrations and notlimitation.

1. A packing element comprising: a mandrel; at least one seal memberhaving a Chevron shape and composed of a metal material; and anenergizer in operable communication with the at least one seal member.2. The packing element as claimed in claim 1 wherein the element furthercomprises at least one slip and at least one ramp in operablecommunication with the mandrel.
 3. The packing element as claimed inclaim 2 wherein the at least one ramp is movable on the mandrel.
 4. Thepacking element as claimed in claim 2 wherein the at least one slip andat least one ramp is two slips and two ramps, one of each operable as aset and responsive to axial compression along the mandrel to increase anoutside diameter of each slip and ramp combination.
 5. The packingelement as claimed in claim 1 wherein the at least one seal membercomprises a stack of seal member elements.
 6. The packing element asclaimed in claim 1 wherein the at least one seal member is two sealmembers having a direction of the Chevron shape of each member opposed.7. The packing element as claimed in claim 1 wherein the energizer is aresilient member.
 8. The packing element as claimed in claim 1 whereinthe energizer is a spring member.
 9. The packing element as claimed inclaim 1 wherein the at least one seal member when actuated creates aseries of relatively narrow annular seals with a target tubular.
 10. Thepacking element as claimed in claim 9 wherein the series of seals are atdifferent relative diameters.
 11. A method of packing a tubularcomprising: compressing a packing element as claimed in claim 1;splaying open at least one seal member to enlarge a radial dimension ofthe member; and maintaining energy in the at least one seal member. 12.The method of packing a tubular as claimed in claim 11 wherein thecompression is axial.
 13. The method of packing a tubular as claimed inclaim 11 wherein the splaying of at least one seal member is splayingopen of a number of sealing elements to cause a number of relativelynarrow annular seals to form against a target tubular.
 14. The method ofpacking a tubular as claimed in claim 13 wherein the relatively narrowannular seals have different diameters.
 15. The method of packing atubular as claimed in claim 11 wherein the maintaining is by compressingan energizer to store energy that is automatically released upon areduction in axial compression of the packing element.
 16. The method ofpacking a tubular as claimed in claim 11 wherein the maintaining is bysetting a ratcheting assembly.
 17. The method of packing a tubular asclaimed in claim 11 wherein the at least one seal member is a number ofseal members, the members each including at least one sealing element.18. The method of packing a tubular as claimed in claim 17 wherein theseal members are a mirror image of one another.